Safety device for punch-presses



C. C. MADSEN.

SAFETY DEVICE FOR PUNCH PRESSESE APPLICATION FILED DEC. 5, 1919.

1,388,354. Patented Aug. 23', 1921.

UNITED STATES PATENT OFFICE.

CHARLES C. MADSEN, OF CHICAGO, ILLINOIS, ASSIGNOR TO KEYSTONE TOOL AND DIE WORKS, TRUSTEE, OF CHICAGOyILLINOIS.

SAFETY DEVICE FOR PUNGH-PRESSES.

Application filed December 5, 1919. Serial No. 342,592.

T 0 all whom it may concern:

Be it known that I, CHARLES C. MADSEN, a citizen of the United States, residing at Chicago, Cook county, Illinois, have invented certain new and useful Improvements in Safety Devices for Punch-Presses, of which the following, taken in connection with the drawings, is a description.

My invention relates to safety devices which are applied to punch presses and the like, and has for its object the arrangement of an apparatus which will prevent accidental operation of the machine while the operators hands or fingers are in a position to be injured by the descending head of the machine.

The principal object of my invention is to construct a machine of this character which is equipped with mechanism whereby the punch press cannot be operated without first actuating mechanism in my safety press which will automatically remove theoperators hands from possible contact with the descending head of the press.

A further object of my invention is to provide a mechanism of this kind which is not dependent in its successful operation upon the mind of the person operating the machine to keep within certain limits of movement, but one which will be entirely automatic in its operation so that it will be entirely impossible for the punch press to be operated whilethe operator has his hands under the operating head of the machine without deliberately placing them there.

It is also an object of my lnvention to provide a means for regulating the operation of this device, which mechanism will be connected with the foot pedal of the punch press in such manner that the press cannot be operated without first operating the mechanism which actuates the guard in advance of the press.

Further objects of advantage of my mechanism will be apparent to those skilled in the art to which this apparatus belongs. In the accompanying drawings I have illustrated what I now consider the preferred embodi-- ment of a device showing my invention applied to a punch press, although I do not desire to be limited to the precise construc tion here shown in the manner of its details.

In these drawings,-Figure 1 is a front elevation of a fragmentary portion of a punch press with my apparatus attached shown in Specification of Letters Patent.

Patented Aug. 23, 1921.

its lowered position when the punch press is at rest.

Fig. 2 is a similar View illustrating the device in raised position with the head of the punch press lowering.

Fig. 3 is a top plan view of my device detached from the punch press.

Fig. 4 is an enlarged detail, partly in section illustrating the foot pedal of the punch press having mounted thereon the auxiliary pedal which has direct connection with. my safety apparatus.

Referring to the drawings A represents the front of a bed plate of the press frame and A the vertical movable head all of which in these drawings Ihave shown in the simplest form to illustrate the principle of my invention.

B represents the vertical movable guard which may be for convenience approximately rectangular in shape, comprising a frame 6 surrounding a wire screen or the like. In the upper part of this frame b I have provided the elongated slots or openings 04, through which are slidably secured one end of each of the arms (If-a by means of pins a a projecting into said slots or openings at.

The arms a a? are angular in shape, one end of each arm being movably' secured through the slot a formed in the upper part of the rim of the guard B. The opposite end of each of these arms extends outwardly beyond the outer edges of the frame of the gua1;d B and are fixedly secured to blocks 0-0 Secured to the bed plate A of the press upon each side of the uard B is a housing or frame B'B l xtending from the blocks cc', and approximately at right angles to the arm, (I -(l are the rods CC, the free ends of which ee are each bent at an angle toward the other as shown more clearly in Fig. 3 and rest in this position when the machine is not being operated.

Surrounding each of the rods CC within the housing members B,B is a coiled spring I) the tension of which is exerted uponthe rods C C to return them to normal position after the guard has been raised to the position shown in Fig. 2.

Attached to one of the blocks, in this instance c which will be on the right hand side of the operator of the machine, is a cord or chain D. which extends to .the auxiliary pedal (Z (shown more clearly in Fig. 4) and is secured thereto at approximately the center of. said pedal cl. The cord D is attached to the block 0 near the periphery thereof in position to transmit a crank movement there to when the pedal d is depressed as hereinafter described.

One end of said pedal (Z is attached to a shaft cl which is preferably supported in suitable bearings in the frame of the machine. The opposite end of this auxiliary pedal (Z is attached to the punch press pedal D by means of which the punch press is operated in the manner well known. A spring (Z normally raises the operating end of the auxiliary pedal (Z out of contact with the pedal D until it is depressed by the action of the operators'foot upon it.

In the operation of this device when the operator has arranged his work on the bed A of the press and is ready to start the machine in operation, the parts are in the relative positions shown in Figs. 1 and 3. \Vhen the head of the press is at rest the guard is in the lowered position as shown in Fig. .1, the arms 6-0 are in the position shown in Fig. 3. When the guard is raised the arms aa", having on the ends thereof the pins, a a which project into the slots (1, moves outwardly, the arms aa raising and carrying the guard upwardly as shown in Fig. 2,

a-*a* are ins attached to the front ofthe bed plate and extend through the guard on either side of the vertical center piece a. By this means the guard is maintained in proper position during its upward and downward movement. Before the head A of the press can be lowered it is necessary for the operator to depress the pedal D. To depress this pedal D the operator is required to first depress the auxiliary pedal d and bring the necessary pressure to bear upon the punch press pedal D. In operating the auxiliary pedal d the opera-- tor has through the cord D connected with the block 0', transmitted a rotating move ment to said block 0 in turning .it from the position shown in Fig. 1 tothe position shown in Fig. 2, and has raised the guard 13 to its elevated position and simultaneously has raised and turned the rods C-C' upwardly and outwardly to clear the. bed plate before the head A of the punch press starts on its downward movement. Thus, if the operators hands were on the opposite side or rim of the guard B (or between the guard and the work on the bed plate) the movement of the rods CC would cause them to push or be forced out of the way before the head A starts on its downward movement, thereby clearing the bed plate entirely of the presence of anything on it other than the workintended to be operated upon. The

same operation-of the foot pedal causes the arms'e-e to be moved on the arc of a circle, the was of wh ch ln'thls instance 1s the corresponding arm CC. It will thus be seen that the body of the punch press must be clear before the head of the punch press de scends. The arms C-C, a-a extend from the blocks 0-0 and the depression of the treadle which has connection by means of the cord Ddirectly to the block 0' will rotate the block a partial turn, carrying with it the red C and the arm M. The effect of this action is to raise the arm a upwardly carrying with it the screen, in which the correspondingarm a'is engaged by means of the pin extending into the slot at. It will be understood that this screen is light in weight andbut little force is necessary to raise it to the position shown in Fig. 2; the engage ment of the pin a through the slot at being sufficient to prevent the guardswinging in of the press, rotatable blocks supported 'on' the bed plate of the press, rods extending therefrom, arms connected with said blocks and having movable connection with said guard, and means for causing said guard to move to elevated position in advance of the operation of the press.

2. A device of the class described comprising a press in combinative relation with a vertically movable guard mounted in front of the bed plate of said press, rotatable 1nemhers supported on the bed plate, outwardly movable arms connected with said rotatable members and normally resting above the bed plate of-the machine, means connected with the mechanism for operating said press to actuate said guard mechanism in advance of each operation of thepress to raise the aforesaid arms and clear the bed plate of the machine in advance of each operation of the press. 4

3. A device of the class described compris ing a press in combinative relation with the vertically movable guard mounted in front of the bed plate of said press, rotatable mem bers supported in the bed plate of the press,

upwardly movable arms connected with said blocks and normally resting abovethe bed plate of the machine, means connected with the mechanism for operating said press to elevate said guard mechanism in advance of each operation of the press and simultaneously to raise the aforesaid arms and clear the bed of the press in advance-of the descending movement of the head, and

means for restoring said guard and the aforesaid arms to normal position.

4. In a device of the class described comprising a punch press having an operating foot pedal connected thereto, in combination with a guard vertically movable in front of the bed plate of said press, rotatable members mounted on the bed plate of the machine, guard arms connected therewith and normally resting above the bed plate of said press, an auxiliary pedal in operative relation with the foot pedal of the punch press and positioned above said punch press pedal, means for elevating the aforesaid guard and raising the guard and arms with the depression of the auxiliary pedal, and spring mechanism restoring said guard and guard arms to normal position after each 0peration of the punch press.

5. In a device of the class described, the combination of a punch ress having an operating foot pedal attac ed thereto, an initially operated auxiliary pedal, a vertically movable guard positioned in front of the bed plate of said press, rotatable blocks mounted on said press, guard arms normally resting above the bed plate of the press, mechanism operated by said auxiliary pedal to actuate the aforesaid guard arms in advance of the operation of the punch press.

6. In a device of the class described, the combination of a punch press having an operating foot pedal attached thereto, an initially operated auxiliary pedal, a vertically movable guard positioned in front of the bed plate of said press, rotatable blocks mounted on the bed plate of the press, guard arms extending therefrom and normally resting above said bed plate, movable connections between the guard and the auxiliary pedal, and means for automatically restoring said guard and guard arms to normal position upon the reverse movement of the press mechanism.

In testimony whereof I have signed this specification.

CHARLES C. MADSEN. 

